


Chisaki Kyoya, Shinsou Mukuro, Shinsou Nagi (Or: How Not to Deal With Death)

by Maven_Fair



Series: In which... [3]
Category: Katekyou Hitman Reborn!, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Angst, Crossover, Dimension Travel, Gen, One Shot, Unhealthy Coping Mechanisms, kyoyas not happy about being chisakis younger brother, mukuro and chrome are sad babies
Language: English
Status: Completed
Published: 2019-07-29
Updated: 2019-07-29
Packaged: 2020-07-19 18:41:33
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,535
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19978717
Author URL: https://archiveofourown.org/users/Maven_Fair/pseuds/Maven_Fair
Summary: In which Kyoya is Chisaki's younger brother, and Mukuro and Chrome are Shinsou's older siblings.





	Chisaki Kyoya, Shinsou Mukuro, Shinsou Nagi (Or: How Not to Deal With Death)

**Author's Note:**

> Guys I wrote this in like a two-hour speed write session. I couldn't stop. It felt great. Anyway, a thank you to everyone who commented, bookmarked, and gave kudos. Enjoy!

To many people, Kyoya was considered unkillable. A constant pillar of how strong the Vongola was, how untouchable. While there was a constant flow of competitors, Kyoya could rarely concern himself with those who he deemed weak. He simply bit them to death. And if that wasn’t enough, he would track down Mukuro and spar.

Weak people were weak. Herbivores were herbivores, and carnivores were carnivores. That’s how Kyoya had spent his life, determining who was worth his time and who wasn’t.

Until Sawada Tsunayoshi rolled around.

He flipped every notion that the world abided by. An herbivore by all accounts except his actions. Slowly but surely, Kyoya reluctantly gave him the title of omnivore. Of course, this weird phenomena was a once-in-a-lifetime thing, and should be observed closely.

So observe Kyoya did. He served as Tsuna’s guardian, battling more and more impressive foes as the years went on, and always coming out on top in one way or another.

It was easy to forget that he could lose. Fon rarely wanted to spar, preferring instead to teach. And even when they did, Kyoya soon surpassed him, to nearly no one’s surprise. Mukuro and his fights were rarely ever lethal enough to harm, knowing that actually killing each other was too much, instead simply reveling in the fights themselves.

So when he was too late to save Tsuna from the attackers, or when Hayato took a bullet to the head because he wasn’t paying attention, or when Takeshi jumped off a building…

Well. Kyoya may not have lost in the traditional sense, yet he lost all the same.

It was hard to admit to himself that he had begun to care for them. So hard to admit that he had instead decided to avoid the topic, seeking out the mafioso who caused their deaths and biting them to death with a zealous fervor.

The Vongola was never the same after Tsuna, Hayato, and Takeshi had died. Reborn went missing somewhere, Ryohei became addicted to training the new generation as well as himself, Lambo pretended to be happy but was obviously falling apart, and Chrome and Mukuro went off to god knows where.

Leaving Kyoya to tend to the Vongola’s defenses.

Normally this would have been fine, but Kyoya had begun to slip. He became so wrapped in the fighting that he wouldn’t notice certain things, only realizing what had happened when he came back to the mansion with more and more injuries as the days progressed.

Of course, he paid it no mind, trusting in his body to protect him

That was his downfall.

He doesn’t even know how it happens, only registering the immense pain before blacking out.

He stays in an annoying limbo for awhile, unable to truly comprehend what’s happening. Is he in heaven? Hell?

His question is answered when he wakes to find a boy with messy raven hair and a medical mask leaning over him. He then notices the other two people, and attempts to remind them that crowding is against the rules and that they need to be punished.

But then his new body decides to start crying right there.

“Boss, do I have to carry him? He’s so… dirty. And loud.”

Kyoya wishes that he was powerful enough to bite him to death. Instead, he settles for glaring menacingly.

* * *

Chisaki Kai is a yakuza member, and Kyoya hates him.

Trapped in the useless body of a baby, he’s forced to depend on those around him to take care of him. He despises the fact that he can’t fend for himself, tied down by physical restraints.

Was this what it was like being a baby in his previous life? Useless to those around him and unable to uphold the peace?

He wonders if this is what being an herbivore feels like. Constantly struggling with your own inability to defend yourself, to contribute to the world. Depending on others to fight for you, to protect you.

But the upsides of being a baby contain one thing and one thing only:

People trust you.

Not the faithful, vigilant trust, the type that Tsuna displayed towards him and the others. Or, had displayed.

No, it was the trust of knowing that you wouldn’t judge, wouldn’t offer unsolicited advice. Would simply sit and listen, without the intention of ever telling anyone else. Or, in Kyoya’s case, without the ability to.

So, he listens. He listens to a member bemoan his troubles with his wife, to another talk about the guilt they felt over killing someone.

Fon had always been better at this, he begrudgingly admits to himself one night, when he has to bite down a glare as Chisaki Kai divulges to him his want to “cleanse” the world.

“Just wait, Kyoya. Someday, I’ll rid the world of the quirk plague that’s gripped our society,” Kai says. They’re outside, facing the traditional Japanese garden. Under normal circumstances, Kyoya would have found peace in its simplistic beauty; nowadays, however, he finds himself constantly on-edge.

“As disgusting as you are, I can appreciate your… quietness. Boss said that babies were loud and annoying, but I can’t see it. You’re so quiet. ” Kyoya doesn’t stoop so long as to gurgle in response, but he comes close.

“I hope that one day you’ll be able to help be along on my goal. Who knows, maybe you’ll end up quirkless,” Kai murmurs the last part, stroking Kyoya’s face with a gloved hand.

“I may be the only one who sees the devastation quirks have brought, but I’m sure you, at least, will understand. I’ll make you understand.” Kai goes quiet then, contemplative. They spend the next half an hour like that, Kai staring out at the night sky, and Kyoya observing him.

Perhaps, one day he would have agreed with Kai. Once upon a time he had wished for the death of all herbivores. But something changed that; Sawada Tsunayoshi changed that. If he had died before becoming an omnivore…

Kyoya doesn’t know if he would have become who he was without him.

(He ignores the twinge of his heart. Thoughts like that are so… herbivorous.)

* * *

Kyoya knows what quirks are, knows Kai’s disdain for them, yet he doesn’t truly understand them. He lives a horribly secluded life, and doesn’t see many instances of quirk usage. Kai seems to have all but banned it.

So he investigates under the guise of being a baby. Underestimating him will be their downfall, he’s sure. He’ll train right under their noses, become so powerful that they won’t stand a chance.

(He had tried to pull upon his cloud flames, just once. Nothing happened, and Kyoya spent the rest of the day on-edge, frustrated and feeling so, so lonely.)

So it comes as a surprise when he finally is let out of the house, seemingly for the first time in this new life. It’s nothing big, just a small visit to the local supermarket, but Kyoya spends the whole time looking at the world around him. He soaks it all up like he’ll never see it again.

And he might not.

Because Kai seemed to have it in his brain that the outside world was “too dangerous” for Kyoya, and had all but locked him up.

So Kyoya observes, makes notes, and wonders what his quirk might be. From what he knows, it’s hereditary, yet Kai doesn’t seem to be all that open to talking about their birth parents.

He hopes it’s powerful. He hopes that it’s like his cloud flames, pushing him from good to great, from great to amazing.

He hopes a lot of things, nowadays. There isn’t much else to do then hope and discreetly train his body and mind.

(He feels like he’s turning into members of his old… family.)

(He had never called them that, before.)

* * *

(Training his body is easy in this world. The yakuza, no matter how honorable, still don’t believe in weak links.

That’s okay, because that’s what will be the downfall of them.)

* * *

Kyoya firsts hears the name Todoroki when he overhears Kai complain about the heroes of this world, citing Endeavor (or Todoroki Enji) as an example.

The second time he hears it is when he’s freshly turned three, and is finally allowed to have alone time. He’s pretending to be interested in some toys when he overhears a lawsuit put against the hero for building damages.

The third time is when he’s watching the news from the corner of the room, pretending to read a book.

He’s four and a half and Kai is sure that he’s quirkless, having had a doctor visit him on his birthday and take an x-ray of his foot. It came back with the toe joint in his pinky toe, meaning he’s likely quirkless. Kai was ecstatic for days afterwards.

So while having no quirk is somewhat of a let-down, Kyoya was formidable even without flames in his previous life, so he doesn’t dwell on it. What he does dwell on, however, is the news report of Endeavor encased in ice.

“… with the incident in question being that of Endeavor’s son, Todoroki Tsunayoshi, awakening his quirk and encasing his father in ice. Countless doctors have tried to understand exactly what the ice is and how to break it, but no results have been found. Meanwhile, authorities are continuing the investigation of Endeavor’s actions the day… ”

And then the screen shows a small picture of Todoroki Tsunayoshi, and Kyoya almost misses it, misses him.

But there’s no mistaking that face, that passion.

Kyoya feels it in his veins, coursing through him like lightning. He feels it bubble to the surface, and he laughs hysterically for a moment, the first time he has ever done that. It guides the members of the room he’s in towards him, the sound foreign and strange.

Kyoya feels it bubble up and over, and feels the soft caress of his violet flames as they incase his whole body, protecting him and giving him strength.

Finally.

* * *

…

* * *

Rokudo Mukuro does not cry. He does not feel, and he does not care for people past the surface level of whether or not they’re useful to him.

Chrome is the opposite of him, her kindness and compassion bleeding out to those in need. Two sides of a coin, they were. Two kids abandoned by the world.

Rokudo Mukuro had no love for the Vongola or the mafia, but at Chrome’s hopeful glances he joined Sawada Tsunayoshi’s little gang, under the guise of wanting to take over his body.

At first it actually was for his body, but as time went on, it became more about the strange interactions he and Chrome had with the rest of his group. The weird feeling in his heart he gets when sparring with Hibari or Sasegawa, the arguments he gets into with Gokudera and Yamamoto, and the quiet moments between him and Sawada.

But he’s still Rokudo Mukuro, still the emotionless monster, so he doesn’t cry when Sawada Tsunayoshi is the first to go, dying from an unhealable wound.

He continues on with life, even as Chrome goes quieter and quieter, preferring to spend time alone than to go out like she used to.

He simply watches as Gokudera falls next, a bullet quickly and efficiently cutting off his misery and guilt that had been more obvious as each day had gone by.

He’s told of Yamamoto’s jump right after he comes back from a mission, Chrome’s eyes watery and so, so sad.

He knows that staying will only continue to hurt.

So he packs up his bags, packs Chrome’s bags, and they head off onto the road under the pretense of checking out Vongola’s allies. It’s like it used to be, so many years ago, just him, Chrome, Ken, and Chikusa.

Many times it feels too quiet.

But they continue on, like they always have, and like they always will.

Until they hear about Hibari Kyoya’s death. It’s sudden and so brutally unexpected. Realistically, Mukuro knew that, one day, Hibari would die, yet he always assumed it would be either by his hand or by old age.

Never from his own flames eating at his body, tearing away at his sanity and leaving him open to the group of mafioso that had mobbed him.

(Mukuro sends their minds through the closest thing to hell on earth once he finds them. And then he kills them, slowly, painstakingly, and allows himself to mourn.)

So Mukuro and Chrome return, allowing Ken and Chikusa to continue on. They weren’t hindered by the responsibility of picking the pieces back up, of fixing the hole that Hibari’s death brings.

Because Hibari was the symbol of power that Mukuro could never be. He was always at the forefront of the battles, never hiding behind illusions or trickery to win. Mafia men quaked in their too-expensive boots whenever they heard the tell-tale signs of Hibari’s approach.

Now that he’s gone, the mafia world is chaos.

And it’s during this chaos that Mukuro grows tired, weary. He had missed his and Hibari’s fights, missed their spars and the moments after the fights when both of them were too tired to move.

Suddenly he wishes he didn’t have to fight at all.

It’s funny, really, how different he is from before he met Sawada Tsunayoshi. Before, it was all about destroying the mafia, and fighting whoever gets in his way.

Now it’s about keeping the peace, fighting alongside allies that seem to all believe what Sawada did:

That the mafia can change for the better.

Yet he still grows tired of the constant fights, the up-and-comers who seem so hellbent on knocking the Vongola down a peg.

Up-and-comers who are as smart as they are vicious, it seems, when Mukuro gets grazed by a gunshot and he calls upon his flames to punish whoever did it before -

Nothing. Absolutely nothing.

His flames are gone, and his last thoughts as his surprise overtakes him and someone stabs him in the throat is that Sawada Tsunayoshi is a liar, and that he hopes Chrome’s okay.

Then he blacks out.

* * *

The pain recedes slowly, replaced by a pleasant and warm state. Mukuro has been through hell and back, so he knows that this is not what dying feels like, not for someone like him.

So he struggles to break the veil, the barrier that separates him from being able to see and feel where he is.

He wakes to a man with truly impressive eyebags leaning over him, changing his… diaper.

Rokudo Mukuro, bearer of the six paths of reincarnation, glares and kicks him petulantly. He turns to observe his new world, new life, when he lays eyes on the baby next to him, who is staring right back.

* * *

…

* * *

Chrome is used to sadness. Her first memory of it is when her parents first start fighting, yelling over her as she plays with the few toys around their house.

Sadness permeates their house, leaving Nagi to walk on eggshells in fear of another outburst.

Her second big memory of sadness is more like a collection of moments. It starts with the car crash, then her parents' refusal to pay for the surgery, and then the subsequent days in the hospital, simply waiting for death to take her.

And then Mukuro-sama comes along and changes all of that.

Soon after she meets Sawada Tsunayoshi and the endless amount of compassion he seemed to have, seemingly caring for allies and enemies alike.

Mukuro-sama hates him, but Chrome cannot help but be drawn in by his charisma and charm.

She joins and fights with them, no matter how reluctant Mukuro-sama seemed. She grows stronger, better than before. She grows strong enough so that what happened with Julie won’t ever happen again.

And then it all comes crashing down.

Tsuna, Gokudera, Yamamoto, even Hibari… All dead, now. Chrome almost couldn’t believe it until they arrived back at the Vongola Manor, until they saw the faces of Sasegawa and Lambo and knew.

They stay strong, for a few months. The power vacuum never happens as people thought, and the search for a successor is still going strong.

And then one moment she’s fighting a few low-level mafioso when she feels her insides suddenly leave her, creating a gaping chasm. She collapses suddenly, the mafioso stunned for only a second before she is hit point-blank by a gunshot.

* * *

Death is pleasant, Chrome supposes. She wonders where Mukuro-sama is, and whether or not she will be able to see him again.

It’s at that thought that the drowsy and warm feeling leaves and she suddenly opens her eyes to a ceiling with a mobile rotating above her. Chrome is confused and disoriented, and tries to move her body only to look down and see the body of a baby.

She turns suddenly, looking left and right for signs of… something, but then lays eyes on the baby next to her.

“I suppose you two gained the family tradition of insomnia, huh Nagi, Mukuro,” the man above them says.

“Mukuro-sama?” she tries to say, but it comes out only as a gurgle. The other baby seems to understand, anyway, and takes her hand in his.

* * *

Life is simple in the Shinsou family. Their new parents (what a weird term) seem to always be awake, or at least one loud sound away from consciousness. Quiet and unassuming seem to be their characteristics, preferring to go about their lives in companionable silence.

Chrome warms to them almost immediately. Shinsou Kouhei and Shizuko are kind and careful with them, as though the slightest misstep could lead to their deaths.

Mukuro is not as easily won over, and it takes as long as two years before he comes around.

By that time they have a younger sibling, Hitoshi.

Hitoshi is so small, so beautiful. Chrome wonders if she ever looked like that. Mukuro wonders if he’ll be useful.

Their life is easy, simple. The Shinsou family are the classic middle class, office worker and stay-at-home mother family. They pretend to be babies, for the most part. Mukuro doesn’t seem to be able to possess people in this world, and the one time they tried to call upon illusions they don’t answer.

(Mukuro looks strangely sick after their attempt, so Chrome doesn’t push to try again.)

The world they arrived in is strange and fascinating in so many ways. Heroes, villains, quirks… all so interesting and new. Mukuro can hardly wait to get his quirk, and Chrome herself is hoping for something close to her old and familiar illusions.

Unfortunately, it doesn’t seem like Kouhei or Shizuko own any type of illusion quirk, and since they’re apparently hereditary, Chrome’s not too hopeful.

So, life is simple. Chrome especially enjoys watching the hero news, interested in the ways of this world’s strange idea of heroism. When she thinks of a hero she thinks of Tsuna, and then her heart grows somber and she distracts herself with looking after Hitoshi, conversing with Mukuro-sama in secret, or anything that makes her momentarily skip over the fact that all the people she used to know (minus Mukuro-sama) seemed to all be dead or in another universe.

She knows it could be worse. She could be alone, for one. She could have parents like before.

Mukuro seems hellbent on becoming as strong as possible. Chrome occasionally sees him muttering to himself over the pros and cons of becoming a hero or becoming a villain.

And then, one day, their new simple life is interrupted.

It’s a quiet day at home, with Kouhei reading a book and sipping tea, Hitoshi gurgling happily as he’s fed by Shizuko, who’s watching TV. Mukuro and Chrome are also watching the TV, but are entirely bored by it. They’re just about to leave when the documentary on jellyfish cuts out to a news broadcast.

“Breaking news: the Endeavor case, as you all know, has been the center of many discussions as of late. For those of you who don’t know, charges of domestic abuse are being investigated due to an incident that happened roughly one week ago. Endeavor’s second youngest son, Todoroki Tsunayoshi, had just discovered his quirk, which appears to be a combination of both fire and ice. He encased Endeavor in ice after he had allegedly slapped his wife, Todoroki Rei. The details of the case can be found at… ”

And. There’s a picture, of the Todoroki family. One tall, red-haired figure. One lithe and frail white-haired figure, holding a baby. Four toddlers standing tall and in a line. But what draws Mukuro and Chrome’s eyes are the youngest, the one that they’ve circled in red.

Because that face is, without a doubt, Sawada Tsunayoshi’s.

Mukuro and Chrome stare transfixed at the TV, until they hear a gasp from Shizuko, and then the breaking of glass from Kouhei. Then they look away to check what’s wrong, until they see that the room seems to be distorted, the floor wavy and the walls contorting in ways that they know aren’t possible.

And then they look down at themselves and see the comforting dark blue flames that encase where they’re holding hands.

“Kufufufu, finally.”

**Author's Note:**

> OC Name Meanings:
> 
> Kouhei: Calm peace 
> 
> Shizuko: Quiet child
> 
> Thanks again for reading! As I said before, I claim no competence in Japanese. I was super excited for this chapter due to the fact that I always knew that Kyoya had to be a Chisaki. It felt too right to not do. Mukuro and Chrome were harder, I went through various people from Nighteye, to Tokoyami, to Hawks, before finally deciding that Shinsou was the best fit. So far, this is the longest of the bunch. Is it obvious that Kyoya is my third fav? (Behind Tsuna and Gokudera, respectively.) Unfortunately, my alliteration was ruined, but alas, not everything can go as planned. Also, no promises, but the next in the series is one I'm very, very excited for. It's pretty obvious who it'll be, but I'm still so hyped. I've got some really fun things planned. Again, thanks for reading, and I hope that you'll continue to support me!


End file.
